[Boatanchors] 813 grid to filament short

[Marvin Match]

Paul Baldock  wrote:
>> The entirety gets back to 813s and mounting them horizontally. Bad
>> move!  W3BYM uses 4 813s to modulate 4 813s.  Should one dig up the
>> old ER issue, you'll find that he mounted them vertically! The only
>> intelligent way to do so.
> Well I'm an intelligent person, I think. At least intelligent enough
> to read the manufacturers data sheet that says " in a horizontal
> position, the base pins No2 and No6 should be positioned vertically
> one above the other"
>
> Then of course there's those beautifully constructed 813 amps in the
> 1968 ARRL handbook
> http://www.arrl.org/files/file/protected/Group/Members/Technology/tis/info/pdf/68hb195.pdf.
> Yes the tubes are on their side, and that seems like a quite an
> intelligent article also.
>
> - Paul

Paul,

Just curious . . . might those be Chinese 813's? If I remember 
correctly, some of the Chinese tubes did not have their elements 
correctly aligned with the pins, therefore placing pins 2 and 6 vertical 
actually places the elements in the wrong orientation.

Just a thought . . .

Otherwise, sometimes they fail just 'cuz.

Marvin
KA7TPH